Rommon A And Rommon B; Upgrading Or Downgrading A Single Node Or All Nodes; Reloading Nodes After A Rommon Firmware Change - Cisco ASR 9000 Series Configuration Manual

ROMMON A and ROMMON B

ROMMON versions are backward compatible. You need not downgrade the ROMMON versions if the
Note
current version is higher than the listed compatible version.
ROMMON A and ROMMON B
Each node in a Cisco ASR 9000 Series Router includes two copies of ROM Monitor: ROMMON A and
ROMMON B. During power on, ROMMON A loads first. If ROMMON A detects the presence of
ROMMON B, it checks the compatibility and integrity of the ROMMON B code. If ROMMON B passes
these tests, ROMMON A passes control of the router to ROMMON B.
Normally, you only upgrade ROMMON B. ROMMON A is a backup for ROMMON B. When you upgrade
the ROMMON B, the router uses the unmodified ROMMON A if the ROM Monitor upgrade is interrupted
or fails for any reason.
Failures are most likely to occur during ROMMON upgrades or downgrades and unlikely to fail during normal
usage. A failure in ROMMON A results in an inactive card that must be returned to the authorized merchandiser.
Note We recommend that you upgrade ROMMON on all the boards to the latest version provided in FPD pie
for any particular release.

Upgrading or Downgrading a Single Node or All Nodes

The upgrade and downgrade procedures for ROMMON firmware are the same. Install a higher version to
upgrade the firmware, or a lower version to downgrade the firmware.
ROM Monitor operates on every node within the router. During an upgrade or downgrade, the ROMMON
firmware is copied into hardware EEPROMs in the router.
For most upgrades, we recommend upgrading or downgrading the ROMMON firmware on all nodes. You
can also upgrade or downgrade a single node, which is useful when moving a card between two routers or
adding a card that is not running the correct ROM Monitor version. When you upgrade a single node that uses
ROM Monitor in both the CPU0 and SP modules, such as a line card node, we recommend that you upgrade
both modules to the same ROM Monitor version.

Reloading Nodes After a ROMMON Firmware Change

The new ROMMON firmware is not active on a node until the card is reloaded. For example, if you upgrade
a single node, you must reload that node only after the upgrade. If you upgrade or downgrade all nodes, you
must also reload all nodes to activate the new ROMMON version.
To gracefully reload all nodes, reload the standby RSP, perform a redundancy switchover, reload the second
RSP, and then reload all other nodes in the system.
If the router does not contain a redundant standby RSP, or if you wish to perform a cold restart, you can also
reload all nodes at the same time, including the primary RSP. Remember that a cold restart results in router
downtime while the cards reboot.
Cisco ASR 9000 Series Aggregation Services Router ROM Monitor Configuration Guide, Release 5.1.x
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Upgrading and Downgrading ROM Monitor Firmware
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